Means for controlling heat exchange apparatus



June 16, 1936. R C 2,044,461

' MEANS FOR CONTROLLING HEAT EXCHANGE APPARATUS Filed July 20, 1934 Orifice '7 v I [cc Bourdan 0 Nozzle INVENTOR Fudg/f Beck.

BY %MLK+$GAL3.

ATTO RNEYs.

Patented June 16, 1936 MEAN S FOR CON TROG Rudolf Beck, Bridgeport,

solidated Ashcroft GE APPARATU Hancock HEAT S Coma, assignor to (ion- Company, Inc.,

Bridgeport, Coma, a corporation of Delaware Application July 20, 1934, Serial No. 736,185

7 Claims.

This invention relates to improvements in apparatus for controlling the temperature and pressure conditions in heat exchange apparatus.

An important object of this invention is to f iy secured by means of this invention.

This invention resides substantially in combination, construction, relative location of in greater detail in In the drawing- Figure lisa diagrammatic view of the appa the arrangement, and parts, all as will be set forth the following specification.

ratus bf this invention showing "some parts in cross section;

Fig. 2 is a detail view of the complete system; and

Fig. 3 is an enlarged vertical central cross-sectional detail view.

It is common practice exchange apparatus, whether it be for the pura modified portion of valve or dam whieh tice in such systems to provide automatic appara us, subject to the temperature conditions of the heat exchange apparatus, for controlling the fiow of the fluid pressure medium. Many forms of apparatus have been devised of this general nature and the general object of this invention is to provide certain improvements in the structure and arrangement of the parts of such apparatus whereby the temperature in the heat exchange apparatus may be very accurately controlled between definite limits and by means of which the inherent frictional forces and time of such apparatusmay be compensated for insure rapid variation and accurate maintenance of temperature or pressure conditions between the desired limits within the heat exchange apparatus.

The true nature and scope of the invention will be set forth in connection with the following detail description.

The heat exchange apparatus, whether it be a heating or a refrigerating machine, is illustrated diagrammatically at 2. The heating or cooling medium is supplied through a pipe which includes the main control controls the flow of heating or cooling medium therethrough to the heat exchange apparatus 2. Within the apparatus 2 is the temperature and/or moved by the spring it into and out of registry part of the apparatus is well known in many forms not be described in further detail. Compressed air or its equivalent, is supplied from any suitable pressure source through the pipe 1 to the various parts of the equipment. Pipe 1 is connected by a branch to the nozzle includes an orifice or restriction 8, likewise in accordance with well known practice. The action of this part of the system is to supply variable air pressure for actuating the remaining parts of the control equipment. I

The variable air pressure thus created is supplied through pipe 25 to a small tank or container 22 which contains a body of oil into which the tube 23 dips so that the variable air pressure through pipe 25 oil body. The upper end of tube 23 communicates apparent. It

is normally urged upwardly by a spring 32. Con- 55 valve I, which of course 10 and need 25 6, which branch 30 acts upon the surface of the 4 on the 45 oil container .22 willhbe described later at ,7

in describing 0 nected to the head 3| is the valve rod I3 of the valve I. This valve rod passes through the usual packing gland 28, which is the source of friction which is compensated for, as will be apparent 5 from the description of the operation. Secured to the valve stem l3 for movement therewith is a rigid arm 26 which is pivotally connected by a link I8 at the point H to a. lever I6, which in turn is pivotally connected at I9 to the lower end 10 of the bellows 9. The end 20 of lever I6 is positioned directly opposite another nozzle I which in turn is connected by a pipe 33 to the fluid pressure supply pipe I on the opposite side of the restriction or orifice II to the point of connec- 15 tion of the branch containing the orifice 8.

It will be noted that the nozzle I0 is a fixed nozzle and that the end 20 of the lever I6 is movable relative thereto. It will also be noted that the link I8 may interconnect the levers I6 20 and the arm 26 at different distances from the pivot point I9, as exemplified by the plurality of holes in the lever and arm. It will also be noted that the bellows 9 is rigidly supported at one end from the arm I4 and is free at its lower end.

The operation of the apparatus will now be given upon the assumption of definite temperatures, pressures, and movements of the parts, since it is believed that the action will be clearer.

30 Assume that the temperature in the heat ex change apparatus 2 is to be maintained between the temperatures of 180 and 182 F. Further assume that at 180 F. the pressure in the bellows '9 is two pounds per square inch, at 181 F. seven 35 pounds per square inch, and at 182 F. twelve pounds per square inch. v Also assume that it is desirable to have the valve I one-half inch open at 180 F., one-quarter inch open at 181 F., and completely closed at 182 F. The bellows 9 is 40 selected so that it will produce a movement at its lower end of one-eighth of an inch in accordance with a pressure change therein between two and seven pounds per square inch, and a movent of one-eighth of an inch between seven and twelve po ur1 c ls per sgu ar i igh c harpgejnaprese sure. The IinlTWis so adjusted that with the valve I one-half inch open and a pressure of two pounds per square inch in the bellows the end 20 of lever IE will be positioned about 0.002 inch 50 from the discharge end of nozzle I0.

A slight increase in pressure in the bellows 9 will cause the end 20 of lever I6 to close the 'nozzETIFsfncrthedownward movement of the various valve sizes, provision is also made for changing the leverage at the joint H, which pivot point may be shifted to the various journal holes on lever I6, thereby permitting a change in the temperature sensitivity of the control 5 apparatus. In the above example it was assumed that a pressure change of two to twelve pounds per square inch was required to cause the valve l3 to travel from fully open to closed position and that bellows 9 would expand a total of onequarter of an inch when exposed to this change in pressure of ten pounds. Now, if the lever length 17:20 is made four times the length of the lever 19:20 the bellows 9 must travel only one-fourth of the one-half inch valve travel, or one-eighth of an inch instead of one-quarter of an inch as before. Suppow then the control spring 4, segment 5, nozzle 6, and orifice 8 produced the ten pound pressure change in the bellows 9 for a temperature change of 2 at the bulb 3. Then, 20 with the above change in leverage, as stated, it will require a temperature change of only 1 at the bulb 3 to cause valve I to move from fully open to fully closed position, or in other words the temperature sensitivity of the apparatus has been doubled.

It is a known fact in this art that when the temperature sensitivity of such a control system is increased there is a likelihood of the development of hunting unless the time factor of the system is adapted to the time factor of the device under control. With the sensitivity set for a 2 variation a throttling control may be obtained, but on changes in demand at the heat exchange apparatus the temperature can adjust itself to any point within the control band of 2. When adjusted to a control band of 1 the valve will react so quickly to temperatureAchangevas-to' move continuously from open to closed position and back'again unless the time factor of the valve, 40 which normally would be somewhere between five and thirty seconds, is considerably increased.

-It is here that the oil tank arrangement 22 comes in to control the time factor of valve I. Pipe 25, instead pipe 21, is connected through the oil device 22 which is, partially filled with oil. As stated, pipe 23 extends below the surface of the oil and terminates near the bottom of the tank. The fluid pressure from pipe 25 acts upon the surface of the oil body. As the pressure increases the oil is forced up into the tube 23. It will be noted that the pipe 21 extends towards and terminates near free end of the bellows will cause'thelever L6Mtheb QttcMwwhen in its contracted 55 to pivot about the point I1. The closing of the nozzle I0 will cause the building up of pressure in pipe 33, pipe I, and the chamber above the diaphragm 30. This will cause the valve stem I3 to move downwardly against the action of spring 32 and move valve I towards closed position. For instance, if bellows 9, under this change in pressure, expands so that its lower end moves one-sixteenth of an inch and the lever ratio 20:19 to 20:17 is 1:2, the valve stem will move two times one-sixteenth of an inch, or oneeighth inch, in a direction to close the valve before position.

On starting up the bellows is filled with air at atmospheric pressure. As the pressure builds up in pipe 25 and on the surface of the oil, the oil is forced upwardly through tube 23 and through the needle valve 24 into the bellows. To build 60 the pressure from zeropounds gau'ge, or fifteen pounds absolute, to twelve pounds gauge, twenty-seven pounds absolute, the, air in the bellows has to be compressed in the ratio of 27 15.

A volume of oil corresponding to 12/2'lths of the 65 volume of the bellows, plus their volume increase the end 20 of lever I6 begins to open the nozzl'efl 0*.-uponexpansion therefore has to be forced through This prevents further movement of valve I. It is obvious, therefore, that the valve will travel 7 proportionately to the bellows, the ratio being determined by the lever ratio 20:19 to 20:17.

To adapt the device to valves of different sizes with different valve lifts, it is only necessary to change this lever ratio. Y Aside from changing the lever proportions for the needle valve to build up the twelve pounds gauge pressure in the bellows. This arrangement permits of .an increase in the time for closing the valve of fifteen to twenty times, as against the use of a needle valve or orifice inserted directly between line 25 and bellows 9.because the time required for a definite volume of liquid to pass through an orifice is very much longer than of being connected directly to4*5*- the time for an qual volume of a gas. By adto produce the proper response of valve l is thus justing the position of. the needle valve 24 the correspondingly similar. time factor of the main valve I can be adjusted Other factors which in a way similar to the to which the apparatus may be applied. valve diaphragm are hysteresis of the diaphragm I This system has certain additional advantages material, which usually is rubber, ageing (stiflenover those which are apparent from the above ing) of the diaphragm, and the generally varydescription. Instead of having a constantly ing pressure of the heating fluid against the changing supply of air coming through needle unbalanced area of the valve disc. All these facvalve 24, which would gradually deposit dirt and tors make the response of the valve irregular.

small orifice to the valve, there is always the pressure to the valve diaphragm directly.

same oil passing to and fro through this valve. With this invention the air pressure produced Any dirt which may be carried in by the air by the thermostatic system in definite ratio to through pipe 25 is either deposited on the surface temperature changes positions the bellows 9 in of the oil or settles through the oil to the bottom exact ratio to the temperature changes, and the of the container 22 and does not reach the needle bellows position in turn controls the valve posivalve. tion in definite ratio, practically irrespective of As will be apparent, this invention is of course the various disturbing factors of the conventional not restricted to the use of a bellows as the presvalve design.

sure responsive element since various other known As this art is fully aware, inventions of this type forms of pressure responsive elements may be are not necessarily limited to use with heat exused. For example, Fig. 2 illustrates a diflerent change apparatus nor are they limited to actuaarrangement in which the Bourdon pressure tube tion by variation in temperature and/or pressure 25 2| is substituted for the bellows in a manner conditions. Such controlsystems,asthe art fully which will be apparent to those skilled in the art; knows, may be employed in the control of many It is also apparent that when desired a presforms of apparatus in which some condition vasure relay may be inserted between the nozzle l0 ries from a set value at which it is desired to or, if the nozzle and orifice were made large work in the same manner whether the heat exenough to give the proper speed ofoperation, too change apparatus be one into which heat is put much air would be wasted. Likewise a relay can or one from which heat is abstracted. For this no be inserted between the nozzle 6 and the bellows 9 reason it is intended in the claims that the exto'increase the sensitivity of this part of the pression "heat exchange apparatus will cover,

apparatus. Such additions are well known in as is well known, both kinds of heat exchange the art and do not change the principle or scope apparatus.

of this invention. From the above description it will be apparent to Further emphasis of the advantages of this that this invention resides in certain principles of system seems desirable. The valve diaphragm construction and operation which may be put friction, generated mostly at the packing gland 28. desire to be strictly limited to the disclosure as This friction is practically' inevitable, especially given in an illustrative sense but rather to the where high pressure valves are employed and a Scope of the appended claims. tight packing is necessary. If the nozzle 6 were What I seek to secure by United States Letters connected directly to the diaphragm motor l2, Patent is: this valve might be closed to within one-quarter 1. In a system of the type described, the comof an inch as the pressure on the diaphragm is bination comprising a heat exchange apparatus rising to seven pounds per square inch. having a supply conduit connected thereto and Assuming that one pound pressure per square 8. pressure motor operated valve in said conduit, inch is required to overcome stumng box fric- -a pressure supply conduit connected to said motion, and supposing the temperature in the heat tor having a bleed port, a pressure responsive exchange apparatus is getting too low, requirdevice for controlling the discharge from said ing the valve to open wider, the friction force bleed port, a fluid pressure supply pipe to said reversing in direction with a reversal of motion device including means for maintaining a mobile of the valve would require a reduction. in the body of liquid in said pipe, said pipe having a pressure on the diaphragm from seven to five bleed port, means for adjustably restricting pounds per square inch befor any movement movement of said liquid, and means subject to of the valve occurred. This means that the temthe temperature in Said heat exchange apparatus fore the valve even begins to move. By interpri.sjng heat exchange appimtus supply 00.nposing the bellows 9 and nozzle m the fact that. duit connected thereto having a valve there1n,

y from the POZZIB This requires ply pipe for the device, means subject to the change of p ure In 9 f 1888 h n pound temperature in the heat exchange apparatus for per square inch as against two pounds in the controlling the fluid pressure in the supply pipe, above case. The drop in temperature required a liquid container in series with said supply pipe,

and an adjustable restriction means for varying the flow of liquid there past to change the rate of response of said device.

3. A system as described, comprising a heat exchange apparatus, a conduit connected to said apparatus having a valve therein, a fluid pressure operated motor for operating said valve, a fluid pressure supply conduit to said motor having a branch terminating in a bleed port, a fluid responsive device, a lever pivotally mounted on said device and positioned to control the bleed port, means for pivotally interconnecting the lever with said fluid pressure operated motor, a fluid pressure supply pipe connected to said device including a liquid container having an adjustable needle valve to restrict the flow of liquid there past, said pipe having. a bleed port, and means subject to the temperature conditions within the heat exchange apparatus for controlling the discharge from said second bleed port.

4. In a system as described, the combination comprising a fluid supply pipe having a pressure fluid motor operated valve therein, a fluid pressure supply conduit for the pressure motor of the valve having a branch with a bleed port, means subject to the variation of a condition to be controlled for varying the discharge of fluid from said port, a pressure responsive element mounted on a fixed support, a connection from said branch to said pressure'responsive device,

a second branch connected to said conduit having a bleed port, a lever pivotally mounted on said pressure responsive device intermediate the ends of the lever, one end of said lever being opposite the second mentioned bleed port, and means interconnecting the other end of said lever with said pressure motor.

5. The combination comprising a valve having a fluid pressure operated motor for operating it, a pipe connected to said motor, means for controlling the flow of fluid through said pipe comprising a valve mechanism of the supply and waste type, a control couple therefor, the relative movement of the elements of the couple governing the operation of said valve mechanism, a pressure responsive device, one of the elements of said couple being pivotally mounted on said device, means for connecting said element to said motor, a second control couple, the relative movement between which governs the supply of pressure fluid to said device, and means responsive to the fluctuations of a variable condition for relatively positioning the elements of the second couple.

6. In an apparatus of the type described, the combination comprising a supply pipe, a valve in said pipe, a pressure fluid operated motor connected to said valve, a pressure fluid supply conduit for said motor having a bleed port, a pressure responsive device mounted on a fixed support, a lever pivotally mounted on said device intermediate the ends of the lever, one end of the lever being positioned opposite said port, means for interconnecting the lever with said motor, a branch connection from said conduit to said pressure responsive device having a bleed port, and means responsive to variations in a condition to be controlled for controlling the discharge of fluid from said second port.

' '7. In an apparatus of the type described, the combination comprising a supply pipe, a valve in said pipe, a pressure fluid operated motor connected to said valve, a pressure fluid supply conduit for said motor having a bleed port, a pressure responsive device mounted on a fixed support, a lever pivotally mounted on said device intermediate the ends of the lever, one end of the lever being positioned opposite said port, means for interconnecting the leverwith said motor, a branch connection from said conduit to said pressure responsive device having a bleed port, means responsive to variations in a condition to be controlled for controlling the discharge of fluid from said second port, means forming in said branch connection a chamber containing a liquid, movements of said liquid operating the pressure responsive device, and means for restricting the movements of said liquid.

R UDOLF BECK. If? 7 

